The invention relates to cross-linked polymer blends including single-site initiated polyolefin resins and polyolefins including ethylene and propylene.
Polymer blends that can be formed (i.e., thermoformed or pressure-formed) are useful in a number of applications, particularly, when the polymer blends have good flexibility properties, high thermal stability, and are foamable. For example, these materials can be used as components in floatation devices for water sports or as sealing or gasket components in, e.g., the automotive industry. Traditionally, the physical properties required by these types of applications suggest the use of high density foams.
In general, polymer blends with these properties are based, in part, on cross-linked ethylene-propylene-diene monomer (EPDM) terpolymers or ethylene-vinyl acetate (EVA) copolymers. These materials generally contain other additives, such as plasticizers, to add to their flexibility. Thermal stability is typically achieved by sulfur vulcanization of the compositions. However, plasticizers can leach out of the materials over time which can make the materials less flexible and the sulfur additives can make the material less desirable for environmental reasons.